This invention employs nip or pinch rollers to force or stuff ribbon into a chamber, the rollers having stripper members on the side toward the chamber to assure that the ribbon enters the chamber rather than winding around the rollers. Such configurations are conventional. The following prior art is illustrative of pinch rollers in such stuffer cartridges, all typically having associated stripper members: U.S. Pat. Nos. 4,538,931 (particularly FIG. 10) to Nagashima, 4,534,667 to Bury, 4,405,247 to Hanna, 4,232,976 to Bernardis et al, 4,229,112 to Schaefer, 4,131,372 to Hengelhaupt, 4,130,367 to Guerrini et al, 4,053,042 to Hess, 3,994,383 to Best, 3,989,132 to Carson, and 3,974,906 to Lee et al.
This invention employs a dam constricting ribbon movement for metering ribbon. Such dams are generally conventional. The following prior art is illustrative of such dams: two U.S. Patents listed above as follows: Nos. 4,232,976 and 3,989,132 and also U.S. Pat. No. 3,814,231 to Cappotto. U.S. Pat. Nos. 4,616,942 to Nagasawa et al and No. 4,388,006 to Waibel show exit chambers defined by a single dam. Ribbon leaves these exit chambers in single strands through an exit slot. This invention has such an exit chamber in close proximity to a wall member situated in the line of force of the drive rollers. In the foregoing 4,388,006 the direction of force appears to be toward the dam, rather than toward a wall member.
The foregoing 4,616,942 has three rollers in the cartridge and a direction of force from the pinch rollers which is toward a wall near the dam. This invention has such a configuration. However, the exit slot is on the side of the exit chamber away from the wall and the dam is perpendicular to the wall, configurations basically opposite from those of this invention. Additionally, the drive roller in this patent borders on the chamber stuffed with ribbon, while in this invention the drive roller is away from the stuffed chamber.
Stuffed cartridge configurations in which nip rollers drive generally toward exit slots are conventional. U.S. Pat. Nos. 4,645,363 to Andersson; 4,623,274 to Ohsaki, 4,465,388 to Iwasawa and 4,325,645 to Miyajima are illustrative. Research Disclosure article No. 28058 entitled "Cartridge Ribbon Restraint System", August 1987, No. 280, Kenneth Mason Publications Ltd., England shows pinch rollers directed toward top and bottom bosses in a stuffed ribbon cartridge.
This invention provides a ribbon stuffer cartridge which operates in the same mechanism of a printer as a spool-to-spool feed cartridge carrying ribbon to be used only once. U.S. Pat. No. 4,131,372, listed above, is of general interest in this respect for its showing of a fabric ribbon cartridge which is driven by a printer with mechanism which also drives a cartridge with another kind of ribbon.
The cartridge of this invention is the same size and general shape as an existing spool-to-spool ribbon cartridge, for example, the cartridge of U.S. Pat. No. 4,523,868 to Shadwick. The drive roller of this cartridge is positioned to be located where the drive roller of such existing cartridge is located, and this cartridge is otherwise compatible with the ribbon feed mechanism of the existing cartridge. This cartridge is therefore interchangeable with such existing cartridge for use on a printer, which was an essential design objective of this cartridge.